Patients with cartilage-wear, deformations or badly healed fractures often suffer from severe pain during movement. For instance, the current treatment is to fixate the subtalar joint (Talus-Calcaneus). This is accompanied by first removing the cartilage and a layer of bone. The bleeding surfaces are then placed upon each other and the bones are fused. Since the joint surfaces in general and the subtalar joint in particular are three-dimensional curvilinear surfaces, it is difficult to reach the entire joint surface with the current surgical tools and procedures. The current fixation procedure involves the use of a hammer and chisel to remove layers of bone from the joint. The current procedure is, therefore, very challenging, cumbersome and imprecise. Most importantly, the joint shape is not preserved due to lack of proper tools. Often an uneven surface is created, possibly resulting in less surface contact, which in turn causes weaker fixation of the joint.
A compliant cutter in published literature (Tuijthof, et al, “A Compliant Instrument for Arthroscopic Joint Fusion”, Proceedings of DETC, ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conferences Salt Lake City, Utah, 2004) works on a similar principle as the subject invention and has a guiding frame, a burr and a multi-piece compliant frame. The frame consists of rings with side wings connected with super-elastic alloy (Nitinol) wires. The cutter was designed for the fusion of the subtalar joint. The authors reported that physical testing of the instrument revealed that it was too flexible and the glued connections between the wires and the rings were not strong enough to hold the components in place. The frame was too flexible to function without adding an additional sleeve. Also, the multi-piece compliant frame consisted of many parts and was difficult to fabricate.